Cannot validate JWT with no kid in its header golang - go

I am trying to verify JWT token provided by a thiredpary, but the token doesn't having the kid in its header. while parsing it showing error message as below
`Error: the JWT has an invalid kid: could not find kid in JWT header`
I am using github.com/golang-jwt/jwt/v4 package to parse
JWT Header contain below values only
{
"alg": "RS256",
"typ": "JWT"
}
related code part given below
// Parse the JWT.
tokenParsed, err := jwt.Parse(token, jwks.Keyfunc)
if err != nil {
ch.Log(alog.FATAL, "Failed to parse the JWT.\nError: %s", err.Error())
}
How can I verify the JWT Token with no kid in its header

Related

Golang Oauth2 Service account returns empty refresh token string

I'm having a problem with the google/Oauth2 package when attempting to authenticate through the service account using a server to server authentication. Google responds with a token struct with an empty refresh token string, and the token expires in 1h, which I can't refresh as I don't have a refresh token.
Here is the code snippet I'm using:
/*
import(
"github.com/google/go-containerregistry/pkg/authn"
gcr "github.com/google/go-containerregistry/pkg/name"
"github.com/google/go-containerregistry/pkg/v1/remote"
)
*/
data, err := ioutil.ReadFile(fmt.Sprintf("%s/%s", path, serviceAccountFilePath))
if err != nil {
log.Fatalf("Failed to read GCP service account key file: %s", err)
}
ctx := context.Background()
fmt.Println(scopes)
creds, err := google.CredentialsFromJSON(ctx, data, scopes...)
if err != nil {
log.Fatalf("Failed to load GCP service account credentials: %s", err)
}
t, _ := creds.TokenSource.Token()
fmt.Println(t.Expiry.Sub(time.Now()).String(), t.RefreshToken, ">>>")
r, err := gcr.NewRegistry("https://gcr.io")
if err != nil {
log.Fatalf("failed to ping registry: %s", err)
}
authToken := authn.FromConfig(authn.AuthConfig{
RegistryToken: t.AccessToken,
})
repo, err := gcr.NewRepository(fmt.Sprintf("%s/%s", urlPrefix, imageName))
repo.Registry = r
list, err := remote.List(repo, remote.WithAuth(authToken))
I tried different ways while using the service account for authentication, such as the config and JWT but I still got the same result.
Service accounts don't need / use refresh tokens.
Refresh tokens are used for offline access by standard Oauth2 authorization. If the user is offline then the application can use the refresh tokens to get an new access token and make requests on behalf of the user.
With service accounts they are already preauthorized and have access to the data they have. A request should return an access token once that access token expires after an hour you just make a new authorization request to get a new access token.
Refresh tokens are unnecessary in the case of service accounts. When the access token expires just run your auth code again to get a new one. Its saving you a step.
Thanks to #DalmTo's hints, I solved the problem.
So the fix for the such problem was by not using the credentials out of google.CredentialsFromJSON() func will return the token source without refreshing the token in case of passing the service account to that function, which means that you can't refresh your token when it expires again later. Also, anticipating and re-authenticating to generate a new token didn't work for me (no clue why).
So I had to convert the JSON of the service account into JWT through this func instead
scopes := []string{"https://www.googleapis.com/auth/cloud-platform"}
tokenSource, err := google.JWTAccessTokenSourceWithScope(serviceAccountFileBytes, scopes...)
The reason that this one works, is because it creates the JWT token internally through the service_account's properties such as client email and client_id and private_key as GCP allows us to create our local JWT tokens and encode them.

How to acquire OAuth2.0 token from Azure AD in Go?

I am attempting to consume Azure service bus entity using Go. Authentication with Azure service bus is possible by supplying either an SAS token or an Azure AD OAuth2.0 token, which will be obtained via the security principals of Azure AD app. Technically I prefer the security principals option rather than an SAS token as it has security vulnerabilities.
How do I acquire an OAuth2.0 token from Azure AD using Go for which Azure AD SDK is not available?
Is it possible to make a direct call to Azure AD REST APIs to access an OAuth2.0 token?
There are some methods to get access token using Go.
1. Use Http Request
For example with authorization code flow, the whole code sample here:
func GetTokens(c AuthorizationConfig, authCode AuthorizationCode, scope string) (t Tokens, err error) {
formVals := url.Values{}
formVals.Set("code", authCode.Value)
formVals.Set("grant_type", "authorization_code")
formVals.Set("redirect_uri", c.RedirectURL())
formVals.Set("scope", scope)
if c.ClientSecret != "" {
formVals.Set("client_secret", c.ClientSecret)
}
formVals.Set("client_id", c.ClientID)
response, err := http.PostForm(TokenURL, formVals)
if err != nil {
return t, errors.Wrap(err, "error while trying to get tokens")
}
body, err := ioutil.ReadAll(response.Body)
if err != nil {
return t, errors.Wrap(err, "error while trying to read token json body")
}
err = json.Unmarshal(body, &t)
if err != nil {
return t, errors.Wrap(err, "error while trying to parse token json body")
}
return
}
2. Use MSAL Go
// 1.1 Initializing a public client:
publicClientapp, err := public.New("client_id", public.WithAuthority("https://login.microsoftonline.com/Enter_The_Tenant_Name_Here"))
// 1.2 Initializing a confidential client:
confidentialClientApp, err := confidential.New("client_id", cred, confidential.WithAuthority("https://login.microsoftonline.com/Enter_The_Tenant_Name_Here"))
// 2. MSAL comes packaged with an in-memory cache. Utilizing the cache is optional, but we would highly recommend it.
var userAccount public.Account
accounts := publicClientApp.Accounts()
if len(accounts) > 0 {
// Assuming the user wanted the first account
userAccount = accounts[0]
// found a cached account, now see if an applicable token has been cached
result, err := publicClientApp.AcquireTokenSilent(context.Background(), []string{"your_scope"}, public.WithSilentAccount(userAccount))
accessToken := result.AccessToken
}
// 3. If there is no suitable token in the cache, or you choose to skip this step, now we can send a request to AAD to obtain a token.
result, err := publicClientApp.AcquireToken"ByOneofTheActualMethods"([]string{"your_scope"}, ...(other parameters depending on the function))
if err != nil {
log.Fatal(err)
}
accessToken := result.AccessToken
Last, Azure SDK for Go seems used to authenticate with Azure, but it doesn't provide a SDK method to acquire an access token.

How to implement authorization using Keycloak

I created a REST API in Go that is necessary an authorization layer, for this layer I am trying use Keycloak. The API will be consumed by a third-party backend service, anyone knows the workflow to integrate Go client and keycloak or already implemented it? I figured out an adapter called Gocloak but in its documentation there is not any example for this purpose.
Authorization is typically application specific, so I can't help much there, but here's some information on authenticating JWTs from Keycloak. After JWTs are authenticated, you can use their claims to authorize the request.
Keycloak exposes what's known as a JSON Web Key Set (JWKS). This resource should be used to authenticate JWTs. I've wrote a package for this purpose. It's an extension of github.com/golang-jwt/jwt/v4.
The package is called github.com/MicahParks/keyfunc. I've pasted the code example for Keycloak below.
package main
import (
"log"
"time"
"github.com/golang-jwt/jwt/v4"
"github.com/MicahParks/keyfunc"
)
func main() {
// Get the JWKS URL.
//
// This is a local Keycloak JWKS endpoint for the master realm.
jwksURL := "http://localhost:8080/auth/realms/master/protocol/openid-connect/certs"
// Create the keyfunc options. Use an error handler that logs. Refresh the JWKS when a JWT signed by an unknown KID
// is found or at the specified interval. Rate limit these refreshes. Timeout the initial JWKS refresh request after
// 10 seconds. This timeout is also used to create the initial context.Context for keyfunc.Get.
options := keyfunc.Options{
RefreshErrorHandler: func(err error) {
log.Printf("There was an error with the jwt.Keyfunc\nError: %s", err.Error())
},
RefreshInterval: time.Hour,
RefreshRateLimit: time.Minute * 5,
RefreshTimeout: time.Second * 10,
RefreshUnknownKID: true,
}
// Create the JWKS from the resource at the given URL.
jwks, err := keyfunc.Get(jwksURL, options)
if err != nil {
log.Fatalf("Failed to create JWKS from resource at the given URL.\nError: %s", err.Error())
}
// Get a JWT to parse.
jwtB64 := "eyJhbGciOiJQUzM4NCIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJMeDFGbWF5UDJZQnR4YXFTMVNLSlJKR2lYUktudzJvdjVXbVlJTUctQkxFIn0.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.Rxrq41AxbWKIQHWv-Tkb7rqwel3sKT_R_AGvn9mPIHqhw1m7nsQWcL9t2a_8MI2hCwgWtYdgTF1xxBNmb2IW3CZkML5nGfcRrFvNaBHd3UQEqbFKZgnIX29h5VoxekyiwFaGD-0RXL83jF7k39hytEzTatwoVjZ-frga0KFl-nLce3OwncRXVCGmxoFzUsyu9TQFS2Mm_p0AMX1y1MAX1JmLC3WFhH3BohhRqpzBtjSfs_f46nE1-HKjqZ1ERrAc2fmiVJjmG7sT702JRuuzrgUpHlMy2juBG4DkVcMlj4neJUmCD1vZyZBRggfaIxNkwUhHtmS2Cp9tOcwNu47tSg"
// Parse the JWT.
token, err := jwt.Parse(jwtB64, jwks.Keyfunc)
if err != nil {
log.Fatalf("Failed to parse the JWT.\nError: %s", err.Error())
}
// Check if the token is valid.
if !token.Valid {
log.Fatalf("The token is not valid.")
}
log.Println("The token is valid.")
// End the background refresh goroutine when it's no longer needed.
jwks.EndBackground()
}

Google Calendar API invalid_grant getting token (Golang)

I'm trying to retrieve an access token, in order to authenticate users using Oauth2. I'm using mostly code found on google's HOW-TO page for using the Calendar API with golang. The problem is that whenever I try to obtain a token, google sends back this:
Response: {
"error" : "invalid_grant"
}
With the error oauth2: cannot fetch token: 400 Bad Request
As I said, I'm using some code got from google's howto, just slightly modified to fit my needs.
//Somewhere...
authURL = config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
//Somewhere else...
func getClient(ctx context.Context, config *oauth2.Config, code string) *http.Client {
cacheFile := tokenCacheFile()
tok, err := tokenFromFile(cacheFile)
if err != nil {
log.Printf("Google auth code not cached. Obtaining from the web...")
tok, err = getTokenFromWeb(code) //This returns an error
if err == nil {
log.Printf("Got token!")
saveToken("calendar-go-quickstart.json", tok)
} else { //Prevent saving token when error
log.Printf("Couldn't get OAUTH2 token! %s", err)
}
}
return config.Client(ctx, tok)
}
The error occurs at "getTokenFromWeb(code)" (if I understood correctly, code must be some random string, no matter its value, it just needs to be the same during the whole process).
This is the problematic code:
func getTokenFromWeb(code string) (*oauth2.Token, error) {
tok, err := config.Exchange(context.Background(), code)
return tok, err
}
After executing, what I see is that error. I even get the exact same error when trying to copy-paste google's own example code!
Any idea? I really can't find a solution online.
Extra details: using IRIS web framework; using the latest version of google calendar api; using the latest version of Golang; I've created a client ID for OAuth2 on Google Cloud Console; The website has got a trusted SSL cert; it listens on port 80 (HTTP) and 4433 (HTTPS);
Here is Google's example:
// getTokenFromWeb uses Config to request a Token.
// It returns the retrieved Token.
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
fmt.Printf("Go to the following link in your browser then type the "+
"authorization code: \n%v\n", authURL)
var code string
if _, err := fmt.Scan(&code); err != nil {
log.Fatalf("Unable to read authorization code %v", err)
}
...
}
code is an authorization code given to the user after visiting the displayed link. fmt.Scan() is going to scan the input from the user.
If you're going to be acting on a different user's behalf, you will have to do something similar to this example.
If you're only acting as yourself, you should be able to authenticate as yourself without the code.
Either way, code cannot be a random string.

Not able to pass Bearer token in headers of a GET request in Golang

I am using oauth2 to access a third party API. I can get the access token alright, but when I try to call the API by passing the bearer token in the request headers it gives me 401 (Unauthorized) error. Although it works well when I try to do it via POSTMAN by passing headers as (Authorization: Bearer ). But it does not work using go.
Here is the code sample.
url := "http://api.kounta.com/v1/companies/me.json"
var bearer = "Bearer " + <ACCESS TOKEN HERE>
req, err := http.NewRequest("GET", url, nil)
req.Header.Add("authorization", bearer)
client := urlfetch.Client(context)
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()
body, _ := ioutil.ReadAll(resp.Body)
writer.Write([]byte(body)) // Gives 401 Unauthorized error, though same works using POSTMAN
I was able to solve the problem. Actually the problem was two way.
1) The API end point was doing a redirect (302), which was causing a 302 response and then the other API was being called.
2) GO by default does not forward the headers, thus my bearer token was being lost in the middle.
FIX:
I had to override the client's CheckRedirect function and manually pass the headers to the new request.
client.CheckRedirect = checkRedirectFunc
Here is how I forwarded the headers manually.
func checkRedirectFunc(req *http.Request, via []*http.Request) error {
req.Header.Add("Authorization", via[0].Header.Get("Authorization"))
return nil
}

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